The present invention features a portable platform for use in gasket seal manufacture.
Several gasket seals are known in the state of the art, especially those of the metallic spiral type spiral wound, double jacketed sleeves and cut non-metallic gaskets.
As shown in FIG. 1, spiral wound gasket 9 is a spiral constituted of a pre-formed metallic strip and a filling of softer material that, by interaction, provide the required sealing. When the initial pressing of the gasket takes place, the filling flows, thereby filling the imperfections of the flange surfaces. The metallic strip has the function of providing mechanical strength. Its xe2x80x98Vxe2x80x99 format, like a chevron ring, allows the gasket to react like a spring, adapting to pressure and temperature variations.
This gasket may be manufactured with diverse combinations of materials, dimensions and shapes, usable in a growing range of applications and providing efficient sealing. Moreover, such gaskets are capable of withstanding high pressures and temperatures at quite low cost.
The simplest model of this type of gasket consists of only a circular spiral, without a centralization ring. Spiral gaskets 9 are used principally in flanges per ASME B.16.5 of the tongue and groove type, as illustrated in FIG. 2, or male and female, as illustrated in FIG. 3. They are also used in equipment, in which there are space and weight limitations, frequent in the chemical and petrochemical industries.
Spiral wound gaskets are manufactured by a simple process, in which a metallic strip together with another strip of non-metallic material are rolled over a metal or wooden mandrel until it forms a spiral, or rather, a spiral wound gasket. Consequently, mandrels of different diameters are utilized to produce gaskets of different diameters.
Another type of known gasket is the gasket of the double jacketed type, which is manufactured from two metallic sheets that are formed over a filler of soft non-metallic material. This gasket, 12, is illustrated in FIG. 4.
There are innumerable types of heat exchangers, many of which are so incorporated into our everyday lives that we take them for granted. In industry diverse types of heat exchanger, some possessing specific names, such as, radiators, boilers, chillers, etc. When we speak in a broad sense about heat exchangers, we may be referring to any of these apparatuses. However, in most industries, it is interpreted as a reference to shell and tube type of heat exchanger. As the name itself indicates, they are devices with a shell and tubes. One of two fluids circulates between the shell and the outside of the tubes and the other fluid inside the tubes.
The double jacketed gaskets, shown in FIGS. 4 and 5, are the most commonly used in heat exchangers. They may be manufactured in various forms, sizes and with partitions for exchangers of with several passes. The primary seal is obtained in the internal side, where there is superimposition of the materials. At this point, the thickness is greater before seating, and the gasket becomes denser after the tightening, occurring the greatest flow of the material and effecting the seal. The outside of the gasket, which also possesses a greater thickness, acts as a secondary seal. The central part of the gasket does not participate decisively in the seal. FIG. 4 shows a sectional view of the double jacketed gasket 12 installed in a tongue and groove.
Due to the fact this type of gasket is quite widely used in heat exchangers, it does not possess standardized dimensions or forms, thereby making its manufacture unviable with a dedicated tool. FIG. 5 illustrates a top view of six typical formats for this type of gasket utilized in heat exchangers.
In the traditionally manufacturing process of double jacketed gaskets, their shape being drawn on a metallic sheet, and then cut out with scissors. The same procedure is followed with a second sheet and a soft filler. The already cut parts are then joined and one of the sheets is formed, with a hammer, on to the other sheets and the soft filler, acquiring the format illustrated in FIGS. 4 and 5.
A third type of known gasket is the non-metallic, or cut, gasket, the simplest and most abundant in industry. Such type of gasket 23, shown in FIG. 6, is cut from gasket sheet, and according to the drawings of the flanges or equipment. The packing sheet is made of the most varied materials, such as graphite, PTFE, aramid fiber, nitrilic rubber derivatives and asbestos (currently in disuse).
The processes of manufacture of these gaskets utilize blades, installed in eccentric or hydraulic presses, which cut such laminates in the formats determined for the gaskets.
The main market for the three types of gaskets above lies in the area of maintenance, there being a variety of types, forms, sizes, materials and applications that, when combined, easily lead the consumer to have to deal with thousands of items. Allied to this is the fact that, during a turn around at a petrochemical plant, a pulp and paper mill, or a refinery, rarely are the gaskets to be changed in the piping, heat exchangers or other equipment known until these are disassembled.
There being a need to replace gaskets, a purchase order for new gaskets is made. However, the delivery of these gaskets from the specialized companies may exceed the machinery maintenance period, thereby delaying the restart of operations and incurring obvious losses.
Another possibility would be to stock various gaskets, which would also be costly.
Thus, it is an objective of the present invention to provide a portable platform to allow the manufacture of gaskets within the production unit, as required, without any need for keeping stocks, consequently reducing costs, besides minimizing the risk of delaying the resumption of productive activities after a gasket leak problem.
A further objective of the present invention is to provide a portable platform, which may be transported from one place to another, in order to accelerate the process of gasket replacement.
When the delivery of an ordered gasket is delayed, there is a risk that the old gasket may be reused and cause a leak, which may, depending on the substance, cause environmental impact.
It should also be taken into account that industrial plants with a high gasket consumption tend more and more to be set up outside the major urban centers, which makes a locally installable machine, which is simple to operate and capable of a broad versatility of types and sizes, a strong distinguishing factor in relation to the competition, as stated above.
The objectives above, among others, are achieved by means of a portable platform for use in the manufacture of gaskets, comprising a shaft, connected to a motor, has the capability of receiving at least one mandrel, and a surface to receive, at least one molding tool, the mandrel being activated by the motor to revolve in relation to the platform and to the tool, and to move gasket-forming elements, such as metallic and non-metallic strips, among others, to be processed by the tool.
According to the present invention, in order to enable a single platform to make different types of gaskets, as much the mandrel as the tool can be changed respectively among mandrel and tools with the following different characteristics, especially those listed below. This enables, therefore, a single platform to make different types of gaskets.
a) A mandrel consisting of a first roller, connected to the motor shaft, and a tool consisting of a set assembly formed of a support base, mounted on a surface of the platform and supporting a compressed air piston, such that its movable tip is connected to a second roller, free to turn. The piston has the purpose of moving the second roller so that its side edges press the elements moved against the side edges of the first roller, pressing them so as to turn them into spiraled gaskets.
b) The mandrel consisting of a first roller, connected to the motor shaft. The tool consisting of an assembly formed of a support base, mounted on a platform surface and supporting a rack that moves a pair of rollers against the first roller. The rack is connected to a rod, at the ends of which the two rollers are respectively attached, such that these are moved by the rack, activated by a lever, so that its side edges press the gasket-forming elements against the side edges of the first roller, such that it presses them, forming a double jacketed gasket.
c) A mandrel consisting of a turntable to place the referred elements and the tool comprising a rod attached to the platform surface and supporting a device for cutting the elements, while they are turned by the plate. In this way, gaskets of the non-metallic or cut type are produced.
Due to the fact that as much the mandrel as the tools may be respectively changed for other mandrels and tools with different characteristics, different types of gaskets may be manufactured, especially, spiral wound, double jacketed and cut non-metallic gaskets on the same platform. Thus, this platform may be moved inside the production unit, in which machines that use such gaskets are installed, and, consequently, speed up and facilitate the gasket replacement process.
As it is a platform conceived to operate in diverse environments, in preferred embodiments, there are separations S inside the body of the platform for the most usual tools T, such as pliers, spanners, sanding tools, welding electrodes, etc., complementing the concept of portability and self-sufficiency in diverse environment.